DNA cloning or gene cloning
CLONING
Cloning is the process by which we can create a copy of an organism that is exactly identical to it. The copy of the organism which is created is called its clone. This clone is genetically identical to the organism. In cloning a single cell of an organism is used to make a genetically identical clone by culturing it in a laboratory. One of the important aspects of cloning is genetic engineering where clones are genetically modified.
There are two types of cloning: natural cloning and artificial cloning. A natural clone is created when an organism reproduces asexually e.g.: yeast. A natural clone can also be created accidentally when an animal has identical twins. This occurs when the zygote splits into two smaller cells and two embryos are formed instead of one.
Artificial cloning is of many different types, (1) DNA cloning (2) reproductive cloning or the cloning of an organism and (3) therapeutic cloning.
DNA cloning or gene cloning
DNA Cloning is a process where a gene is taken from one animal and inserted into another animal where it can be used and studied. Cloning a gene means isolating an exact copy of a single gene from an organism. Usually this involves copying the DNA sequence of that gene into a smaller, more accessible piece of DNA, such as a bacterial plasmid. This makes it easier to study the function of the individual gene in the laboratory. Scientists studying a particular gene often use bacterial plasmids to generate multiple copies of the same gene. DNA Cloning is usually done for research.e.g: it can be used to study a gene that causes disease in an organism and modify it or remove it to prevent that disease.
Organism cloning
Organism cloning is the process by which an entire organism can be cloned. By this process, an organism is generated that has the same DNA as another animal. The process of organism cloning involves the 'somatic cell transfer process' (SCNT). In this process scientists transfer genetic material from the nucleus of a donor cell (an adult cell) to another egg whose original genetic material has been removed. The new egg which contains the DNA of the donor cells is then specially treated so it starts dividing. Once the new cell becomes an embryo and reaches a suitable stage it is transferred to the uterus of a female where it develops until birth. Like in the case of dolly the sheep the clone is not always identical to the donor. Not all the clones genes will come from the donor, some of the genetic material will come from the mitochondria of the new egg. Mitochondria contain their own short segments of DNA.
Therapeutic cloning
Therapeutic cloning is a type of cloning where new human embryos are produced for research. The embryos that are used can be both human and animal embryos. The goal of therapeutic cloning is not to create clones but to harvest stem cells that are used to study human development and help researchers treat diseases. Stem cells are very important and useful cells. Stem cells can be used to create any specialized cells in the human body e.g.: cells of the liver ,skin ,heart etc. there are many ethical concerns over therapeutic cloning because the embryos used to create the stem cells are destroyed. Stem cells can also be used to get organs for organ transplants.
Genetically modified (GM) foods
Cloning can also be used to genetically modify food crops so that they produce more seeds and better seeds and that don't get diseases. These foods are called genetically modified (GM) foods. There has been a lot of controversy over whether these foods should be consumed or not. Many scientists feel that if we eat these foods they can create many problems like diseases for us in the future. Thus, even though GM foods are available to us people are still in doubt as to whether they should consume them.UK has recently given ...
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Genetically modified (GM) foods
Cloning can also be used to genetically modify food crops so that they produce more seeds and better seeds and that don't get diseases. These foods are called genetically modified (GM) foods. There has been a lot of controversy over whether these foods should be consumed or not. Many scientists feel that if we eat these foods they can create many problems like diseases for us in the future. Thus, even though GM foods are available to us people are still in doubt as to whether they should consume them.UK has recently given the go ahead for farmers to grow GM crops. This has come after a long debate in the UK as to whether GM crops should be grown. US scientists are warning of a serious risk to human health after the discovery that traditional varieties of major American food crops are widely contaminated by DNA sequences from GM crops. Crops engineered to produce industrial chemicals and drugs GM crops could already be poisoning GM-free crops grown for food in the US. This has raised concern over GM crops all over the world. GM crops can also have a very bad impact on farmland wildlife due to the harmful chemicals that they produce.
Should humans be cloned?
Many people are very opposed to cloning humans. The U.S. Congress has passed a bill to ban human cloning which would make it a crime to even attempt human cloning and to ship, receive or import cloned embryos or products derived from them. Many people feel that it is unethical and immoral to clone humans. The human genome project which is researching the human genome plans to give scientists more information on human cloning.
Last year advanced cell technologies in Worcester, Massachusetts announced that it had cloned a human embryo. An Italian doctor, Severino Antinori has said that he has cloned and implanted a human embryo in a woman's uterus. Clonaid, an American company promise to clone a human baby for $200,000.cloning humans is still be very risky and needs more research. Researchers have not only cloned sheep like dolly but they have also cloned other animals like cats, monkeys, mice, goats, pigs, rabbits, etc. Attempts to clone other species have also been unsuccessful and very few cloned animals have survived. The genes of cloned mice are severely compromised and aren't functioning properly. The same may happen if we clone humans. Religion also has to be taken into consideration if we want to clone humans. Many religions feel that we shouldn't clone people and 'play god'. After the religious sect the Raelians claimed they had successfully given birth to the first cloned human baby, everyone in the US Congress agreed on the need for a ban on the practice. The Raelians believe that humans are created by aliens and are strong advocates of cloning. They say that they have already cloned a human child.
Dolly the sheep
Dolly the sheep was the world first cloned mammal. She has recently died at the age of 6.she had to be killed by lethal injection because she was suffering from lung cancer and severe arthritis. Although most sheep live to the age of 11 and 12 she died early. The postmortem indication indicated that she was quite normal apart from her cancer and arthritis. She was famously cloned by Dr. Ian Wilmut of the rosin institute, Edinburgh, Scotland. She was the first sheep to be cloned after 276 unsuccessful attempts .Dr. Wilmut himself isn't ruling out that Dolly's arthritis was a symptom of her cloning origins. Dolly also had many problems with weight; she was very overweight and constantly on drugs. Her death reopens the debate on cloning and its problems. She is the worlds most famous cloned animal.
The advantages of cloning
. Therapeutic cloning can solve the problems of many people who have defective organs or problems with their organs like lungs, liver, etc. by using stem cells to grow organs. Human clones can also be created to donate their organs. To prevent rejection of the new organs the cells used to generate stem cells and grow the organs can be taken from the patients themselves.
2. Couples who can't have children due to sterility or other reasons can still have children who resemble them and are genetically identical to them through cloning. Even if the woman is sterile she can still have the child from her body if the scientists implant the embryo in her uterus.
3. Cloning can be used to obtain treatments for diseases like Parkinson's disease, diabetes, heart disease, kidney aliments, cancer, hepatitis, multiple sclerosis, cystic fibrosis, etc. The techniques of cloning form an integral part in the effort to prepare advanced medicines for diagnosis, vaccines and for the treatment of various diseases. Thousands of patients benefit from these techniques.
4. Hereditary diseases can also be prevented through cloning by detecting whether a baby has any diseases through its genes and preparing early for any disease which could even save its life. With cloning we can also have children with the characteristics of parents even if one parent suffers from a serious genetic illness. In this process the scientist who clones the child ensures that it gets that particular gene from the parent who does not have the illness. Doctors can also eliminate strands of DNA that cause deformation and diseases like Down syndrome to ensure that a healthy child is born.
5. Animals can also be cloned with human genes so that their organs can be used for human transplants. E.g.: the British company IMUTRAN is mass producing hogs to donate organs. This has an added advantage because the organs will be cloned from animals and cannot be rejected. Animals that are endangered can be cloned to increase their numbers and be repopulated .Through cloning extinct animals may also be brought back. It will be a very significant achievement if this happens. Researchers are already trying to clone a frozen wooly mammoth. Extinct animals can be cloned through the cells that are in the bone marrow of their skeletons. We can also clone deceased pets.
6. We may be able to clone many great people like Einstein, Newton and Aristotle for the benefit of mankind. e.g.: we could clone someone like Aristotle who, instead of practicing philosophy could be building rockets or solving the problems that mankind are facing.
7. Human diseases can be researched by studying animal clones like mice which are genetically engineered to carry disease carrying mutation in their genes.
8. Genetically modified animals are being produced in large numbers to produce drugs or proteins that are useful in medicine. e.g.: bacteria producing insulin for diabetic patients
9. Cloning through genetic engineering will also give parents the right to choose what characteristics they want in their children to have. It is the parent's ambition to want their children to have certain characteristics.
Disadvantages of cloning
. Cloning can be immoral. Many religious groups and people believe that 'man should not play god'. They also believe that genetic engineering is unnatural and 'people should not overstep their bounds'. Many people also believe that cloning and genetic engineering are wrong because they generate dangerous attitudes towards children, especially those with disease. They also believe that children who are cloned are psychologically affected by it.
2. Most species are interrelated by food chains in nature. Scientists think that introducing genetically modified animals to the wild will disrupt food chains.
3. Cloning is very expensive and highly inefficient .more than 90% of cloning experiments fail to produce results. There is a very high failure rate due to many reasons. The main reason are due to the improper development of the egg with the newly transferred nucleus and the egg not being able to attach itself to the uterus wall.
4. Cloned animals have higher rates of infection, disorders, die early and have many other problems. e.g.: about a third of cloned calves born alive died young and had poor health. Cloned animals have been found to be much bigger than normal animals and have abnormally large organs. Clones can have many defects e.g. cows that were cloned were less attentive and intelligent than normal cows. Cloning also causes imbalance in animal's protein, hormone and fat levels.
5. Sometimes scientists can make mistakes when modifying the genetic material of animals (imprinting genes) causing abnormalities. This can be a great risk with humans. Most imprinting errors occur when embryonic stem cells are being cultured in laboratories.
6. Through cloning there is the possibility of compromising individuality, creativity and freedom. If each person is cloned many times there would be a lot of people who are alike, creating confusion. People would have nothing unique about them. The clones could even take over the identity of original people.
7. Sometimes the women who are carrying the cloned embryos may themselves face pregnancy complications.
8. Cloning will cause us to lose our diversity. The beauty of humanity lies in the differences between people. with cloning everyone would look the same, act the same and be the same
9. Some people are resistant to certain diseases and others are not. This is usually through genes. If people were cloned and had the same genes then they would all be at risk of getting the same disease that they were all not resistant too and being wiped out. This could even happen to the entire human race if everyone on earth had the same genes.
0. In a way it would be inhumane to clone people because clones will not be considered as individuals or humans. They will be considered as a person's property and may even be sold .It will be unethical to sell humans even if they are cloned humans.
1. People may abuse cloning technology to do illegal and immoral things by creating clones for their own purposes.
2. If a child was cloned and became disfigured due to some error the parent's dreams will be shattered and they would have to try and get a child by cloning an embryo again. This way thousands of embryos will be destroyed. This is also the case with animal cloning. Researchers believe that it is unethical to destroy embryos that will eventually form children. e.g.: a cloned cow recently died weeks after its birth with a huge abnormality in blood pressure. The same could happen to human clones leading to questions over the ethics of cloning.
Conclusion
Cloning has both its advantages and disadvantages. I am not opposed to further research into human cloning to find out whether it will be possible to clone humans or not. I also feel that additional research should be done for animal cloning to see whether it should be continued. I am still not sure about the plans to start cloning humans. I fell that without doing proper research into the problems that are there in cloning and solving the problems we shouldn't start cloning humans.
All information for this work was taken from:
http://english.people.com.cn/200108/01/eng20010801_76227.html
http://www.newscientist.com/hottopics/gm/
http://www.globalchange.com/clonlink.htm
http://www.ornl.gov/sci/techresources/Human_Genome/elsi/cloning.shtml
http://www.humancloning.org/
http://gslc.genetics.utah.edu/units/cloning/
The examples were taken from:
http://www.newscientist.com/hottopics/cloning/
http://www.ornl.gov/sci/techresources/Human_Genome/elsi/cloning.shtml
http://www.humancloning.org/
http://english.people.com.cn/200108/01/eng20010801_76227.html
